Smaller is Better

Mouse tumor cells stain red, showing penetration of anticancer drug after 24 hours. Ashutosh Chilikoti

A new nanoparticle that targets tumors, releases its cancer-killing payload, and then dissolves harmlessly may change the way that cancer treatments are delivered.

Research conducted by Ashutosh Chilkoti, Theo Pilkington Professor of biomedical engineering, has shown that when mice with tumors are injected with a nanoparticle made up of a polypeptide molecule combined with the chemotherapy drug doxorubicin, they live three times as long as those treated with doxorubicin alone.

Nano-delivery systems are especially efficient at getting into tumors. Blood vessels that supply tumors are more porous than normal blood vessels, meaning that the small particles carrying the drugs can slip through and accumulate within tumor cells more easily. Higher doses of the drug can be delivered, increasing its cancer-killing abilities while decreasing side effects.

In addition to producing greater reductions in tumor size, the research is significant because of the way the nanoparticle was produced. Large quantities can be made simply and inexpensively. Escherichia coli, a common bacterium, is a reliable, high-yield producer of the specific polypeptides used in the experiments.